/Engine/Source/Editor/Experimental/EditorInteractiveToolsFramework/Public/InteractiveToolStack.h
To use tool stacks, simply add aUToolStackContextto your relevant interactive tools context. This can be done by calling 'AddContextObject' to the context object store of your tool context. See: 'UWidgetEditorToolPaletteMode::Enter' as reference.
struct FInteractiveToolStack
TArray< TPair< ...
OriginalStack
Original stack ordering
TArray< TPair< ...
SortedToolStack
Tools contained within this stack along with their input chord, sorted by most recently used